Assuming you have my Air Meter book I have the following for sale:
ECO 97 or 98: http://petrolianacollectibles.com/restored%20ecos.htm
ECO 97 with coin box, only one ever found, unrestored $1800.00, see page 60,
ECO 28 (1924), completely restored and working, $2000.00, see page 49.
Romort 31D, the only twin head ever made, completely restored, both heads calibrated and working, asking $12,000 but will take a reasonable offer. Page 120.
Romort 41, wall mount, completely restored, calibrated and working, $1700.00. Page 120.
Air-Scale Jr., restored, working condition unknown. $1200.00, page 16.
Petroquip, possibly made in London, England, sold in Canada. Restored, working condition unknown. $700.00, page 27.
Email me and I will post pictures on my website: www.petrocollect.com
All plus shipping.